Die head



im 0- O. HOELZEL ,913

DIE HE'AD Filed June 2'7, 1928 f I I INVENTOR (9M0 BY ATTORNEY Patented Jan. 7, 1930 UNITED STATES PATENT QFFKIE OTTO HOELZEL, OF NEW HAVEN,'CONHECTEGUT, ASfiZGrNOR TO THE EASTERN MACHINE SCREW CORPORATION, GE NEVJ HAVEN, CQNNECTICUT DIE HEAD Application filed June 27,

This invention relates to thread cutting tools of the character known in the trade as die-heads, it being an improvement relat ing particularly to the front plate of a die head arranged to operate in a vertical position to cut threads on loosely hanging bolts, said front plate is provided with a centrally located concave seat adapted to serve as means for guiding the bolt central with respect to the thread cutting chasers of the die head.

A further object of the invention consists in providing openings within the concave seat extending through the front plate to serve as means for breaking up the waste metal forced upward by the chasers into particles fine enough to be washed back again through said openings by means of the thread cutting compound.

Referring to the accompanying drawings wherein the same characters of reference indicate like parts throughout the several views:

Figure 1 represents the front plate of a die head showing the centrally located concave seat and openings therethrough Figure 2 is an elevation partly in section of the front plate on line 22 of Figure 1 Figure 3 is a broken side elevation of a bolt carrier with a bolt depending loosely therefrom, which bolt is shown out of alignment with the center of the thread cutting field of the die head- Figure 4: is a broken front elevation of the bolt carrier shown in alignment with the thread cutting field, and

Figure 5 is a vertical elevation of a. die head and broken view of the pipe for discharging the thread cutting lubricant to the CllZtSc'l s. I

The front plate 1 has the central concave seat 2 extending nearly through said plate, and which will hereinafter be more fully described and all of its advantages clearly brought out.

In general use the die heads are horizontally positioned for thread cutting, but in the present case, in threading rough bolts, a more economical result is obtained by placing the die head in a vertical position.

To more clearly illustrate the operation and 1928. Serial No. 283,617.

advantage of the improved die head, I have shown herewith a boltcarrier 3 having the wide slot 4 for the head 5, and the narrower slot 6 for the body of the bolt 7.

As the bolts are rough and vary in size, these slots will naturally be made sufiiciently to give perfect freedom to the head and body of the bolt. In consequence of this nece sary arrangement, it is obvious that a pc ct alignment of the bolt with the center ,i the die head could not always be assured unless guided toward the center.

"er-ring to Figure 3, it will be observed toe loosely hanging bolt has been adced beyond the dotted line 8, representing the center of the die head 9, and when the end of the bolt is brought into forcible contact with the concave seat 2 of the front plate, said concave seat will force the bolt into the central position represented by the dotted line 8 in Figure l.

Means, not shown, are necessarily provided for rotating the die head and also vertically reciprocating either the die head or bolt carrier. V

in thread cutting, the metal removed by the chassis curls outward in unbroken strings whether the die head is horizontally or vertically positioned. When the die head is in a horizontal position the front plate of the die head is provided with an opening large enough to give free egress to these strings which would otherwise tangle up With the work and Chasers.

in the present vertical position of the die head the concave seat 2 occupies most of this larger opening'and merges into thesmaller opening 11, which opening need be no larger than to afford free passage for the bolt. lVere it not for the radial openings 12 projecting through said seat and the front plate for the escape of the waste metal, such waste metal would be forced back into the die head and clog the chasers. As the strings of waste metal enter these radial openings they are readily en up into small chips by th head p In cutting threads on loosely hanging rough bolts it is absolutelynecessary to give them a certain amount of freedom to prevent their starting crooked in the chasers. While the slot tin-the bolt carrier is wide enough to ive the necessary freedom for automatical y centralizing the bolt with respect to the ehasers, the side Walls 14 of the slot are adapted to be engaged by the corners of the head 5 to prevent rotation of the bolt during the thread cutting operation.

While I show the front plate of the die rovided with guiding means for centralizing a bolt with respect to the thread cutting chasers, it would clearly come within the scope of my invention to apply similar means in the end of such die heads as have no front plate.

The means for supporting a bolt form no part of the present invention, it is simply shown to illustrate the operation and advantage of the novel feature employed for fcentralizing a loosely supported bolt.

As the guiding seat 2 is the only means employed for locating the bolt with respect to V the Chasers, its diameter should naturally correspond to the freedom allowed the bolt, so that the end of the bolt would be sure to 'lie within the area of this seat and thus avoid all hand guiding that would evidently tend to the slowing .up of production. This feature would apply equally as well with the die head: horizontally positioned.

Having thus described my invention what I clairniszj V In a. bolt threading die head,-a front plate for said head having a centrally disposed opening to receive a bolt, and having a con- :comminuted by thewalls of said slots and cave depression in said plate and surrounding said opening for guiding a bolt to the V latter, said plate being provided with a plu-. rality of slots disposed within the confines of the concave depression and connecting the central opening whereby waste material is 5 discharged through said" late.

In testimony whereof afiix my signature.

OTTO 'HOELZEL. 

